#include<bits/stdc++.h>
#define fi first
#define se second
#define ll long long
#define pb push_back
using namespace std;
ll n,d,q,a[300005],r[300005],b[300005],bu[300005];
bool sub2=true;
int main()
{
ios::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
// freopen(".INP","r",stdin);
// freopen(".OUT","w",stdout);
cin>>n>>d;
for(int i=1;i<=n;i++)
{
cin>>a[i];
r[i]=a[i]%d;
}
cin>>q;
if(q<=3000)
{
while(q--)
{
bool kt=true;
int l,rr;
ll mx=1e9;
cin>>l>>rr;
b[l]=0;
bu[l]=(a[l]-d*b[l]-r[l])/d;
if(bu[l]<0)
{
cout<<-1<<endl;
continue;
}
mx=bu[l];
for(int i=l+1;i<=rr;i++)
{
if(r[i]<r[i-1]) b[i]=b[i-1]+1;
else b[i]=b[i-1];
bu[i]=(a[i]-d*b[i]-r[i])/d;
if(bu[i]<0)
{
kt=false;
break;
}
mx=min(mx,bu[i]);
}
if(!kt)
{
cout<<-1<<endl;
continue;
}
int ans=0;
for(int i=l;i<=rr;i++)
{
ans+=(a[i]-(b[i]+mx)*d-r[i])/d;
}
cout<<ans<<endl;
}
return 0;
}
return 0;
}
